蛋白质-聚氨基酸偶联物的高效合成与应用

蛋白质-高分子偶联物是重要的临床药物,可用于多种疾病的治疗.寻找新的生物可降解高分子材料来替代传统的聚乙二醇和发展高效、位点特异性的偶联方法是该领域目前所面临的2个重要挑战.聚氨基酸是一类具有较好生物相容性、可生物降解、含有丰富侧链官能团的仿生功能高分子,在蛋白质修饰方面具有突出的优势,是有较大潜力的聚乙二醇替代物.本专论主要从新型α-氨基酸-N-羧基酸酐(Ncarboxyanhydrides,NCA)可控开环聚合方法、聚氨基酸原位官能化制备位点特异性蛋白质偶联物、扩展功能聚氨基酸分子库调控蛋白质功能等3个方面详细介绍蛋白质-聚氨基酸领域的研究进展,并对这类新型偶联物的发展进行了简单的评述和展望.     

氮氧自由基与氨基酸偶联物的设计合成与结构表征

将对甲酰基苯甲酸分别与氨基乙酸甲酯和4-氨基丁酸甲酯生成酰胺后,再分别与2,3-二甲基-2,3-二羟氨基丁烷进行缩合反应,最后经高碘酸钠氧化得到两种氮氧自由基与氨基酸偶联物,并通过IR、EPR、EI-MS和元素分析对目标化合物的结构进行了表征.     

聚氨基酸在材料科学及生物医药中的二级结构效应

聚氨基酸不仅具有优异的生物相容性和生物可降解性,其类似于蛋白质的二级结构(α-螺旋、β-折叠、无规卷曲)及二级结构的响应性转变赋予了聚氨基酸不同于常规聚合物的特殊功能,在材料及生物医药领域具有重要应用。本文简要概述了本课题组近年来围绕聚氨基酸二级结构在聚合物防污涂层、纳米颗粒-细胞膜相互作用以及蛋白质改性研究中的新进展,并对聚氨基酸二级结构未来的发展方向进行了简要的展望。     

聚（2,5—二甲氧基对苯乙炔）的可溶性前聚物合成及表征

研究了合成聚（２，４－二甲氧基对苯乙炔）的有机可溶性前聚物的反应条件与单体转化率和前聚物产率的关系。实验结果表明：ＮａＯＨ是聚合反应的有效引发剂，适宜的反应条件为：单体与ＮａＯＨ摩尔比为１：１，单体浓度０．０５－０．２ｍｏｌ／Ｌ，聚合时间２ｈ，温度低５℃，正己烷、石油醚作为有机提取剂可有效提高前聚物产率。用ＩＲ、ＵＶ－Ｖｉｓ＇＾ＨＮＭＲ，ＴＧＡ和 ＤＳＣ对前聚物进行了表征。     

沙利多胺与叶酸偶联物的合成研究

本文报道了沙利多胺与叶酸偶联物的合成方法。以廉价易得的邻苯二甲酸酐和谷氨酰胺为原料通过酰化、环合反应得到沙利多胺,沙利多胺与37%甲醛溶液通过羟甲基化反应得到N-羟甲基沙利多胺,再与N-羟基琥珀酰亚胺(NHS)活化的叶酸通过偶联反应得到目标化合物。合成的关键中间体和目标化合物的物性与文献一致,其结构经核磁共振氢谱确认。     

合成紫杉醇-奥曲肽偶联物的新方法

以紫杉醇丁二酸酯为原料,二苯基-N-琥珀酰亚胺磷酸酯为催化剂,合成了中间体N-羟基丁二酰亚胺紫杉醇丁二酸酯(3);3与游离奥曲肽偶联得紫杉醇-奥曲肽偶联物,纯度98%,其结构经ESI-MS确证。     

硝酸锌与四种α-氨基酸配合物的恒容燃烧能测定

Ten solid complexes of zinc nitrate with L-α-leucine(Leu)， L-α-valine(Val)， L-α-tryptophan(Try) and L-α-threonine(Thr) were prepared in water. The compositions of these complexes are determined by chemical analysis and elemental analysis， which are identified as Zn(Leu)(NO₃)₂·2H₂O(A)， Zn(Leu)₂(NO₃)₂·H₂O(B)， Zn(Val)(NO₃)₂·2H₂O(C)， Zn(Val)₂(NO₃)₂·H₂O(D)， Zn(Val)₃(NO₃)₂·H₂O(E)， Zn(Try)(NO₃)₂·2H₂O(F)， Zn(Try)₂(NO₃)₂·H₂O(G)， Zn(Thr)(NO₃)₂·2H₂O(H)， Zn(Thr)₂(NO₃)₂·H₂O(I) and Zn(Thr)₃(NO₃)·H₂O(J). The constant-volume combustion energies of the complexes， Δ_cU(complex)， were determined by a precise rotating bomb calorimeter at 298.15K. Standard enthalpies of combustion，Δ_cH_m^?(complex， s， 298.15K)， and standard enthalpies of formation， Δ_fH_m^?(complex，s，298.15K) for these complexes were calculated as (4523.22±2.08)， (7208.86±4.28)， (3442.21±1.85)， (5971.21±3.32)， (9007.26±4.24)， (5802.35±2.14)， (10891.58±3.01)， (2147.40±1.28)， (4120.83±0.99)， (6444.68±3.85)kJ·mol^-1 and (615.67±2.27)， (1863.16±4.60)， (1017.34±2.00)， (1742.93±3.61)， (2245.70±4.73)， (1161.18±2.61)， (1829.71±4.20)， (1632.82±1.43)， (1885.55±1.50)， (2770.25±4.21)kJ·mol^-1， respectively.     

过渡金属氨基酸席夫碱配合物的合成

合成了6个过渡金属氨基酸席夫碱配合物——L-酪氨酸缩水杨醛合铬(钼),L-赖氨酸缩水杨醛合铬(钼),DL-α-丙氨酸缩水杨醛合铬(钼),其结构经UV,IR和元素分析表征。UV测定结果表明,配合物均可与DNA发生插入作用。     

温度响应性高分子偶联干扰素-α有效提高抗肿瘤功效

利用定点原位生长技术,合成了一种温度响应性的干扰素-聚(2-甲基-2-丙烯酸-2-(2-甲氧基乙氧基)乙酯)偶联物(IFN-PDEGMA).当温度低于22oC时,IFN-PDEGMA处于溶解状态;当温度高于22oC时,IFN-PDEGMA则会发生聚集.由于小鼠体温高于22oC,因此,将IFN-PDEGMA原位注射到小鼠肿瘤组织处之后,它会在肿瘤组织处聚集驻留.体外实验结果显示,IFN-PDEGMA有效保持了干扰素的结构和活性;动物实验结果显示,相比于原药IFN-α,非温敏性IFN-POEGMA、商业化的长效干扰素PEGASYS以及IFN-PDEGMA可以更好地聚集驻留在肿瘤处,荷黑色素瘤小鼠的生存时间得以显著延长,分子量为10 kD a、30 kD a、60 k Da、100 kD a的IFN-PDEGMA所治疗的小鼠,其生存时间分别为36.5、31、29.5、28天,其中,10 kD a和30 kD a的IFN-PDEGMA的治疗效果均要优于PEGASYS.同时,生物安全性实验显示IFN-PDEGMA对正常组织器官不存在显著的毒副作用.     

氨基酸酯-烷基醚混合取代聚膦腈的合成与表征

聚膦腈高聚物,因其良好的生物相容性而用作生物医用材料。若在其侧链引入对热(如烷氧基醚)或对pH值敏感和可生物降解的基团(如氨基酸酯),则可得到具有环境敏感性和可生物降解性能的高聚物,这些高聚物可望作为药物载体,用于药物的控制释放。     

Reaction of amino acid derivatives with C_(60)

Ammo acid derivatives react with C60 at 110-120℃to form adduct compounds.The products were isolated by column chromatography and were identified by FD-MS,UV-Vis,FT-IR and 13C NMR spectroscopies.     

N-二异丙氧磷酰化氨基酸的合成

以亚磷酸二异丙酯为磷酰化试剂、次氯酸钠为氯代试剂首次对20种常见的α-氨基酸进行了磷酰化.通过添加适量四丁基溴化铵为相转移催化剂,使用过量的亚磷酸二异丙酯以补偿其在强碱环境中的水解,从而提高了反应产率.所得产物经核磁共振谱、红外光谱和质谱鉴定结构并分析总结了该类化合物的谱图特征规律.     

Synthesis and characterization of poly(vinylpyrrolidone-co-vinylphosphonic acid) copolymers

Radical copolymerizations of 1-vinyl-2-pyrrolidone (VP) with vinylphosphonic acid (VPA) at different feed ratios were investigated. The copolymers were characterized by ¹H-NMR, ¹³C-NMR and FT-IR. The copolymer composition was determined from the elemental analysis. Thermogravimetric analysis (TG) illustrates that the copolymers are stable up to 200 °C. Temperature dependence of the alternating current (AC) conductivities were investigated by means of impedance spectroscopy. The direct current (DC) conductivities of the samples are derived from the AC conductivity data.     

Poly(amino acid)-based thermoresponsive molecularly imprinted magnetic nanoparticles for specific recognition and release of lysozyme

In this study, poly(amino acid)-based thermoresponsive molecularly imprinted magnetic nanoparticles for recognition and release of lysozyme was prepared via surface imprinting method. For constructing the molecularly imprinted polymer (MIP) layer, amino acid-based thermoresponsive monomer (N-methacryloyl-l-alanine methyl ester, MA-L-Ala-OMe) was mainly selected for the functional monomer along with N,N′-methylenebis(acrylamide) as the crosslinker. The resultant magnetic MIP nanoparticles were characterized in detail. Meanwhile, the dynamic light scattering studies and swelling ratios measurements were carried out for demonstrating the thermoresponsive property of the imprinted nanoparticles. The prepared magnetic MIP nanoparticles showed good adsorption capacity and selective recognition properties to lysozyme. Moreover, the fast adsorption process could reach equilibrium within 15 min. Importantly, the capture and release of lysozyme could be easily realized simply by altering the temperature of aqueous solution. Furthermore, the prepared imprinted nanoparticles were applied to separate lysozyme from the real egg white samples. The results proved that the thermoresponsive MIPs based on MA-L-Ala-OMe have great potential for selectively enriching target proteins in real samples.     

苯胺链段为侧基的聚酰胺酸的合成及性质

采用三元共聚法制备了苯胺齐聚物为侧链的接枝型聚酰胺酸. 通过红外光谱、核磁共振谱及高效凝胶渗透色谱等技术对聚合物结构进行了表征. 该材料亚胺化后具有十分优异的热稳定性. 紫外-可见光谱和电化学测试结果表明, 该聚合物具有独特的光谱性质和可逆的电化学活性. 聚酰胺酸/ITO电致变色电极具有颜色变化明显, 响应速度较快, 着色效率高等优点, 是一种综合性能较好的电致变色聚合物材料.     

聚L-谷氨酸可注射水凝胶的制备及性能

通过活化改性聚L-谷氨酸（PLGA）制备酰肼化PLGA（PLGA-ADH）和3-氨基-1,2-丙二醇改性的PLGA（PLGA-OH）,PLGA-OH经高碘酸钠氧化制得醛基化PLGA（PLGA-CHO）,以PLGA-ADH和PLGA-CHO为前驱体,通过席夫碱交联反应构建了PLGA可注射水凝胶.研究了酰肼化和醛基化改性前后PLGA的结构变化,考察了固含量对水凝胶成胶时间、溶胀行为、机械性能、体外降解性能、药物释放行为及微观形貌等的影响,并进行了初步的细胞培养实验及裸鼠皮下注射成胶实验.结果表明,该PLGA可注射水凝胶在组织工程领域具有良好的应用前景.     

Binding of a surfactant counterion to low-charge-density poly(acrylic acid) and poly(methacrylic acid)

The binding of a cationic surfactant, dodecylpyridinium (C12Py) chloride, with a low-charge-density poly (methacrylic acid) (PMA) was investigated in buffer solutions under the condition of constant pH. The binding isotherms with PMA consisted of two and three steps at a pH lower and higher than 3.2, respectively. Bindings in the first step were independent of pH and this step was considered to correspond to the solubilization of the hydrocarbon chains of C12Py into the nonpolar region of the compact form of PMA. This is the indication of the compact form from the binding isotherm. At pH higher than 3.2, the second step was discriminated and it depended on the pH. In the third step, a sharp rise in the degree of binding (β) was observed accompanying the solubilization of the precipitates of the PMA–C12Py complex. The binding with poly(acrylic acid) (PAA) and PMA in conventional unbuffered NaCl solutions was also examined and the pH profile of the solution during the binding process was determined. In the case of unbuffered NaCl solutions, the binding with PAA took place cooperatively at the critical association concentration (cac). The binding isotherm consisted of two steps and the pH decreased with the increase in β. The binding isotherm of PMA, on the other hand, consisted of three steps: the pH decreased slightly in the first step and considerably in the second step with the increase in β but it increased with β in the third step, exhibiting a pH minimum around 3.2. The binding in the first step coincided with that obtained in the buffered solutions. Linear relationships between β and the pH were found for both polymers. In the case of PMA, no cac was observed in both buffered and unbuffered NaCl solutions. Received: 24 January 2001 Accepted: 23 May 2001     

水相法合成双(环戊二烯基)钛氨基酸配合物的研究

以N-(取代苯基)氨基乙酸及盐与双(环戊二烯基)二氯化钛在水相及有机相反应,得到了五个双(环戊二烯基)钛氨基酸配合物,对配合物进行了熔点、元素分析、IR及^1HNMR的表征,确定了它们的结构。这些配合物在空气中稳定。经比较,水相中的合成反应速度快,操作简便,产物较易分离,产率高。     

Drug-induced hierarchical self-assembly of poly(amino acid) for efficient intracellular drug delivery

As a potent anticancer drug, gambogic acid (GA) suffers from its poor water solubility and low chemical stability and shows a limited clinical outcome. To address this problem, we report here a simple and effective strategy to immobilize and deliver GA using a reducible diblock poly(amino acid) as a model. The electrostatic interaction between GA and polymer enables a high drug loading content up to 53.6 %. Moreover, the drug complexation induces a micelle-to-vesicle transformation, combined with a conformation transition from random coil to α-helix. The hierarchically assembled drug nanocomplexes can serve as a smart carrier for efficient cell internalization and triggered release of multiple drugs under intracellular acidic and reductive conditions, resulting in a synergistic antitumor efficacy in vitro. This work provides a new insight into the drug-carrier interaction and a facile nanoplatform for drug delivery applications.